Hand Pollination and New Bean Varieties

venom_within(8b - 9a)February 5, 2008

Hello everyone. I have posted this message in the bean, pea and legume forum, and they referred me here, so I thought I'd repost it. I have purchased Carol Deppe's book, Breeding Your Own Vegetable Varieties, but it has not arrived yet. That being said, here goes:

I've decided to (hopefully) develop my own strains of Phaseolus vulgaris by intentionally cross-breeding different heirloom strains by hand pollination.

I'm having quite a difficult time finding any information on this topic anywhere online. Hopefully, fellow gardeners around the world here can help me :)

First off, has anyone here had any success hand pollinating perfect flowers? I've read that most beans pollinate themselves before the flower even opens. One website suggested removing the stamen the evening before the morning the flower is due to open, then pollinating the pistil the next day with pollen from the prospective "mate". Is there another way to go about this, or any advise on the best way to accomplish this?

Secondly, it seems to me that most beans can be used as snap, shell and dry beans, depending on the maturity level of the pods, only some cultivars are better suited for one or the other. If crossing, for instance, a pinto bean with a blue lake bush bean, would you treat the F1's as a dry bean, or a green (snap) bean? or both, and decide which is best?

Which brings me to my main question: which traits are dominant and recessive when it comes to Phaseolus vulgaris?

string - stringless pod type

green - yellow - purple - striped pod color

bush - pole growth habit

white - black - mottled - any combination thereof seed color

straight - curved pod shape

flat - rounded pod shape

snap - wax - shell - dry - cranberry bean suitability

flavor and texture?

These are all traits I would like to work with, but only a few at a time of course. I'd like to start off small scale, and work my way up to much larger breeding experiments.

Also, I do understand Mendelian genetics, and the F1 "hybrids" are not my goal. Letting the F1's self pollinate, I will plant the second generation (F2's) and begin selecting the more desirable trait combinations to begin the new strains.

ANY help at all would be greatly appreciated, especially concerning the dominant/recessive traits. Knowing that will let me know if I succeded in crossing the beans.

Carol Deppe also wrote a book " breeding for farmers" or something like that . In most types the bush type is bred in to make it easier to harvest , the pole type would yeild more but be harder to mechanically harvest . stringless traits like "lazy wife " long pod strains like the runner beans , color , disease resistance , earliness, protein content are also things that you might want to consider. Good Luck!

Where would you find information pertaining to the protein content of particular cultivar of bean? In fact, is there a good way (or group) to determine all the nutrition facts of new varieties of beans?

And is it possible to test for disease resistance without actually purposefully exposing them to the diseases? I'm sure it'd be quite ill advised to try and obtain strains of diseases known to wipe out american crops, especially in this day and age.

I have still not been able to find a table or site of some sort detailing which traits are dominant, recessive, codominant or other when it comes to beans. I've seen a few based off of Mendel's experiments with the peas, but I'm not sure if Phaseolus vulgaris' traits follow the same pattern, as other plants/animals do not. (There are species of snakes with several different genes affecting the production of melanin, and some are codominant and others simple recessive and both can be present simultaneously) I just don't want to base my experiments on peas and end up with totally different paths of inheritance...

The Bean Improvement Cooperative page has a .pdf link to a "Bean Genes List 2008." The list seems to use the standard system of capitalizing dominant genes so, for example St gives a stringless pod and st gives a complete string, but other genes can modify this. Note that after page 13 you will get into a list of obsolete gene symbols.

As for testing for protein content, I don't know. An Extreme Melon Growing page (long) mentions using a handheld refractometer to measure sugar content. There are many refractometers on eBay, including a veterinary model for measuring protein in urine. So, could you run fresh beans through a juice machine and consistently dilute with water to get a useful protein measurement?

For real testing you can look for a lab like this University of Missouri lab. But they test leaves, not beans, so you're getting an indirect measurement. Also, the sample size of 20 or 50 leaves means you would be testing multiple plants, presumably either varieties you want to use as parents or a new variety you have stabilized.

All who have tried have found much difficulty in crossing papilionaceous flowers. Several years ago, Dr. Herbert remarked to me that with the exception of Erythrina no hybrids had been made in this great family. Gaertner crossed 36 flowers of different varieties of the common Pea, and he did not get a single pod perfectly developed and with the full complement of seed; he crossed 10 flowers of Kidney Beans, and did not get a single pod. Some years ago I crossed the varieties of the Sweet Pea, and many more flowers dropped off unimpregnated than were fertilised. The difficulty arises from the anthers opening at so early an age that they must be removed long before the flower expands. After the operation the immature stigma is liable to exposure to the air; and it is difficult to judge when to apply the pollen. Moreover there is some reason to suspect that the stigma requires successive applications of pollen. To show the difficulty of fertilising papilionaceous flowers, I may mention that I lately removed all the pollen that I could with a soft brush from six recently expanded flowers of Lupinus pilosus protected from the visits of insects, and then applied pollen from a distinct individual of the same species. Although in this case there was no operation at an early age, yet five flowers out of the six dropped off unimpregnated. Had the flowers remained untouched, all, judging from the others, probably would have set, and the only difference would have been that their stigmas would have been surrounded by a mass of pollen as long as the flowers continued in bloom. This case is worth mentioning as showing how erroneous the belief is that fertilisation usually takes place in unopened flowers, in which the pollen is shed at an early age. These trials on the Lupines, and others formerly on Sweet Peas, led me to try the following plan. I rolled up thin paper into a cylinder, rather thinner than a knitting needle. I then tied a thread tight round, and cut off the cylinder beneath the thread, so that a little pipe closed at one end or cap, about the fifth of an inch, was left. This was easily filled with pollen from the keel-petal of any desired variety, and could then be placed on the pistil and secured below the stigma by being tied with a thread. I then castrated four flower-buds of the Sweet Pea, and placed on the young stigma caps filled with pollen from another variety, and four fine pods were soon formed. I also fertilised eight castrated flowers of two species of Lupins with pollen from distinct plants of the same species, but from these I have got only four pods. I may add, that as an experiment I filled one of the little caps with pollen of Lathyrus grandiflorus and placed it on the stigma of a Sweet Pea (Lathyrus odoratus), and to my great surprise, considering how distinct these species are, a fine pod has been formed. I am certain no pollen could have been left in the flower of the Sweet Pea, as the anthers were removed whilst quite immature; and if these hybrid seeds grow, a curious hybrid will be produced. I should not have thought this plan of fertilising papilionaceous flowers worth mentioning had it not been applicable in all cases in which early castration is necessary, and likewise in certain cases mentioned by Gaertner, in which the stigma requires, or is benefited by, successive applications of pollen. In all such cases some trouble would be saved and certainty gained by the use of the little caps filled with the desired kind of pollen.